1. Field of the Invention
The present invention relates to new dithioketene derivatives which exhibit excellent therapeutic and prophylactic effect for hepatic diseases and pharmaceutical compositions containing these compounds at a dose suitable for daily administration.
2. Description Of The Prior Art
Dialkyl 2-(1,3-dithietan-2-ylidene)malonates and the preparation thereof are disclosed in Ger. Offen. 2,625,220, 2,316,921 and Japan 74 39,260.
Dialkyl 2-(1,3-dithiolan-2-ylidene)malonates are disclosed in Japan Kokai 75 100,062, Japan 75 39,666 and 74 39,260.
Dithiolane derivatives, having a ketone functional group in the side chain, are disclosed in Japan Kokai Tokyo Koho JP 59 27,887.
Dithietane derivatives containing two ketone functional groups in the side chain are disclosed in Japan Kokai Tokyo Koho JP 62 158, 274 and Eur. Pat. Appl. EP 234,480.
Also, reference can be made in U.S. Ser. No. 206,659, which was filed by the same applicant of the present invention.